Traditionally, artists have relied on various mechanical devices (e.g., calibers) and manual methods (e.g., using circles or a head size of a body to proportionally compare each part of the body) to measure and/or compare proportions of their artwork. Alternatively, some artists have relied upon projectors to project an image onto a surface on which the artist intends to work. Such techniques are generally employed when an artist wants to take a small image and paint a larger version of the small image onto a surface larger than that small image, typically of a much greater magnitude of size. Accordingly, a projector may be used to project the small image onto a larger surface, such as by projecting a scaled, larger image of the small image onto the larger surface. However, such projectors (e.g., overhead projectors, digital projectors, etc.) are typically used to project the image onto a flat surface, such as a wall, generally at a perpendicular angle. However, under certain conditions, the image may be projected onto a surface that is not flat (e.g., curved, angled, etc.). Additionally, the image may be projected onto the surface at a non-perpendicular angle relative to the projector, which may result in keystoning.
Accordingly, some projectors are configured to compensate for such surfaces, such as by applying a keystone correction (i.e., skewing the image), which results in a rectangular image being projected, often at the expense of the quality of resolution of the image being projected. Presently, two methods of keystone correction can be implemented: manual and digital. Manual keystone correction is generally accomplished by making a physical adjustment of the lens of the projection; however, manual keystone correction typically cannot eliminate horizontal keystoning. Digital keystone correction is generally accomplished by scaling or otherwise altering the image prior to the image being sent to the lens for projection; however, digital keystone correction results in a squared image, even at an angle.